The reserved car at Denver airport, a compact SUV (Toyota RAV4), was not available. I was offered a minivan instead, which was unacceptable to me. The only car left was a Toyota Highlander, a 3-row family SUV, too big for my needs to drive on narrow mountain roads. I had no choice but to take it. When I got to the car, it was a heavily damaged one, with many scratches and dents. It was dirty inside and already had 32,000 miles on it. It should never have been rented out. During my trip, a warning came on that the RCTW and BSM was no longer working. It was due to the rear damage on the bumper that pushed sensors out of alignment. When I called SIXT, I was offended (by a heavily-Chinese-accented CR) to take a 7-hour ride back to Denver to exchange the car, which was unacceptable to me. I was left with no choice but to continue driving the unsafe car. I have rented many cars in the past, this has been the worst experience ever. I will post this feedback on review websites to warn off other potential SIXT renters.